<template>
  <!-- 商品分类导航 -->
  <div class="type-nav" @mouseenter="enterShow" @mouseleave="leaveShow">
    <div class="container">
      <h2 class="all">全部商品分类</h2>
      <nav class="nav">
        <a href="###">服装城</a>
        <a href="###">美妆馆</a>
        <a href="###">尚品汇超市</a>
        <a href="###">全球购</a>
        <a href="###">闪购</a>
        <a href="###">团购</a>
        <a href="###">有趣</a>
        <a href="###">秒杀</a>
      </nav>
      <!-- 三级联动 -->
      <!-- 过渡动画 -->
      <transition name="sort">
        <div class="sort" v-show="show">
          <!-- 事件委托+编程式导航：实现路由跳转与传递参数 -->
          <div class="all-sort-list2" @click="goSearch">
            <div class="item" v-for="c1 in categoryList" :key="c1.categoryId">
              <h3>
                <a :data-categoryName="c1.categoryName" :data-category1Id="c1.categoryId">
                  {{ c1.categoryName }}
                </a>
              </h3>
              <div class="item-list clearfix">
                <div class="subitem" v-for="c2 in c1.categoryChild" :key="c2.categoryId">
                  <dl class="fore">
                    <dt>
                      <a :data-categoryName="c2.categoryName" :data-category2Id="c2.categoryId">
                        {{ c2.categoryName }}
                      </a>
                    </dt>
                    <dd>
                      <em v-for="c3 in c2.categoryChild" :key="c3.categoryId">
                        <a :data-categoryName="c3.categoryName" :data-category3Id="c3.categoryId">
                          {{ c3.categoryName }}
                        </a>
                      </em>
                    </dd>
                  </dl>
                </div>
              </div>
            </div>
          </div>
        </div>
      </transition>
    </div>
  </div>
</template>

<script>
import { mapState } from 'vuex'
export default {
  name: 'TypeNav',
  data() {
    return {
      show: true
    }
  },
  mounted() {
    // 不在home主页时，隐藏侧边导航栏
    if (this.$route.path != '/home') {
      this.show = false
    }
  },
  computed: {
    ...mapState({
      // 右边为函数，执行一次计算属性，右边函数被执行一次
      categoryList: state => {
        // console.log(state)
        // console.log(state.homeStore.categoryList)
        return state.homeStore.categoryList
      }
    })
  },
  methods: {
    // 三级联动路由跳转函数
    goSearch(event) {
      // 最佳方法：事件委派+编程式导航
      // 问题1：如何判断是a标签节点【有h3、dt、dl、em、a】？
      // 解决1：给a标签添加自定义属性data-categoryName
      // 问题2：如何判断是哪一级标签？
      // 解决2：给相应标签添加data-category?Id自定义属性
      // 获取标签自定义属性：event.target.dataset
      // console.log(event.target.dataset)
      // 结构出来
      let { categoryname, category1id, category2id, category3id } = event.target.dataset
      // 标签上有categoryname属性，则是a标签
      if (categoryname) {
        // 整理路由参数
        let location = { name: 'search' }
        let query = { categoryName: categoryname }
        // 一级、二级、三级分类a标签
        if (category1id) {
          query.category1Id = category1id
        } else if (category2id) {
          query.category2Id = category2id
        } else {
          query.category3Id = category3id
        }
        // 判断路由跳转时是否有params参数，有需带上
        if (this.$route.params) {
          // console.log(this.$route.params)
          // params参数
          location.params = this.$route.params
          // query参数
          location.query = query
          // 编程式跳转
          this.$router.push(location)
        }
      }
    },
    // 鼠标移入，显示侧边分类导航
    enterShow() {
      if (this.$route.path != '/home') {
        this.show = true
      }
    },
    // 鼠标离开，隐藏侧边分类导航
    leaveShow() {
      if (this.$route.path != '/home') {
        this.show = false
      }
    }
  }
}
</script>

<style lang="less" scoped>
.type-nav {
  border-bottom: 2px solid #e1251b;

  .container {
    width: 1200px;
    margin: 0 auto;
    display: flex;
    position: relative;

    .all {
      width: 210px;
      height: 45px;
      background-color: #e1251b;
      line-height: 45px;
      text-align: center;
      color: #fff;
      font-size: 14px;
      font-weight: bold;
    }

    .nav {
      a {
        height: 45px;
        margin: 0 22px;
        line-height: 45px;
        font-size: 16px;
        color: #333;
      }
    }

    .sort {
      position: absolute;
      left: 0;
      top: 45px;
      width: 210px;
      height: 461px;
      position: absolute;
      background: #fafafa;
      z-index: 999;

      a:hover {
        cursor: pointer;
      }

      .all-sort-list2 {
        .item {
          h3 {
            line-height: 30px;
            font-size: 14px;
            font-weight: 400;
            overflow: hidden;
            padding: 0 20px;
            margin: 0;

            a {
              color: #333;
              text-decoration-line: none;
            }
          }

          :hover {
            background-color: skyblue;
          }

          .item-list {
            display: none;
            position: absolute;
            width: 734px;
            min-height: 460px;
            background: #f7f7f7;
            left: 210px;
            border: 1px solid #ddd;
            top: 0;
            z-index: 9999 !important;

            .subitem {
              float: left;
              width: 650px;
              padding: 0 4px 0 8px;

              dl {
                border-top: 1px solid #eee;
                padding: 6px 0;
                overflow: hidden;
                zoom: 1;

                &.fore {
                  border-top: 0;
                }

                dt {
                  float: left;
                  width: 54px;
                  line-height: 22px;
                  text-align: right;
                  padding: 3px 6px 0 0;
                  font-weight: 700;
                }

                dd {
                  float: left;
                  width: 415px;
                  padding: 3px 0 0;
                  overflow: hidden;

                  em {
                    float: left;
                    height: 14px;
                    line-height: 14px;
                    padding: 0 8px;
                    margin-top: 5px;
                    border-left: 1px solid #ccc;
                  }
                }
              }
            }
          }

          &:hover {
            .item-list {
              display: block;
            }
          }
        }
      }
    }

    // 过渡动画
    // 过渡开始
    .sort-enter {
      height: 0px;
    }
    // 过渡完成
    .sort-enter-to {
      height: 461px;
    }
    // 过渡时间、速度
    .sort-enter-active {
      transition: all 0.2s linear;
    }
  }
}
</style>
